DESIGN AND DEVELOPMENT OF AN ONION-PEELING MACHINE

Abstract

An onion peeling machine suitable for farm-level operation was designed and tested for medium-sizeMichigan onions. The novelty of the machine was four scoring blades assisted by compressed air jets to slit the outerlayers of the onion skin. The compressed air penetrated through the slits to loosen and dislodge the skin from the bulb. Apair of high-speed saw blades were used to trim the ends of the onion. Two co-rotating rollers assisted by threecompressed air jets were utilized to spin scored and trimmed onions for final removal and separation of onion peels.<br><br>Tests were made to determine peeling performance as affected by onion size, onion shape, compressed-air pressure,and onion feeding rate (chain speed). The performance of the machine was characterized by peeling efficiency, peelinglosses, and throughput rate. Feeding chain speed and air pressure significantly affected the machines performance. Theinteractions of onion size with air pressure and onion shape with chain speed significantly affected all performanceparameters. Peeling efficiency as high as 89% was obtained while peeling losses were as low as 17%. An estimatedaverage peeling capacity of about 750 kg/h could be obtained using 8.89 cm (3.5 in.) onions.